Electric machines, such as electric motors, can be large and bulky. The larger they get and the more energy they generate or draw the issue of cooling gets increasingly important.
High Ingress Protection index electrical motors do for instance often use a water to air heat exchanger to cool the air inside an enclosure containing the motor. This is very convenient in marine applications for example where water is readily available, but might be not possible in some other working environments or when water close to electrical components must be avoided.
It is also known to use air-to-air heat exchangers in motors. One example on this is given in U.S. Pat. No. 5,844,333, where motor air is cooled through passing coolant tubes with ambient air.
Another type of heat-exchanger that has been used is the heat-pipe. A single frame including a heat-pipe array for an electric motor is described in U.S. Pat. No. 6,499,532.
One interesting technology that exists is the thermosyphon cooling technique.
This technology is for instance used in relation to cooling of electric components, which is described in US 2002/0014324 and EP 2031332. EP 2031332 describes a very compact heat exchanging unit, which is interesting to use also in other areas.
Thermosyphon based cooling has also been previously used in relation to electric machines. US 2005/156470 does for instance describe the cooling of a stator using a thermosyphon unit.
Finally also U.S. Pat. No. 7,102,267 describes the use of thermosyphon technique in relation to an electric machine. In this document the heat exchanging elements used are however bulky.
It would therefore be of interest to improve on the cooling elements described in this latter document.
The present invention is therefore directed towards providing an electric machine being cooled using a more compact thermosyphon based heat exchanging structure.